Enbridge required the double block and bleed isolation on the pipeline as part of a scheduled line shutdown to facilitate the repair of a receiver valve. It was also required that the project be completed without the need to use or leave traditional hot-tap tees on the pipeline system.
STATS believes that this is the first onshore piggable solution of its type completed in Canada.
STATS Group proposed the use of a 48 inch Remote Tecno Plug to complete the valve isolation scope on the client’s PN50 (ANSI Class 300) transmission pipeline.
STATS said that conventional isolations of this type would involve a traditional lip seal line-stop and vents to achieve an isolation that is not guaranteed to be leak-free or a proveable double-block and bleed in the context of Alberta’s Occupational Health and Safety hazardous energy requirements.
The Remote Tecno Plug system offered a proveable, testable and monitorable isolation in-situ in the pipeline system, thereby avoiding additional tie-in weldments for the isolation tool or vent fittings.
The Remote Tecno Plug involves pigging the Tecno Plug from the client’s existing launcher or receiver to the isolation location, and then reverse pigging back to the receiver after performing the isolation. This has positive time, cost and safety benefits over traditional methods.
Managed locally in Edmonton, Alberta, the project involved detailed pipe stress analysis, Canadian Registration Number registration, lock indentation mark assessment and a piggability assessment.
A site survey, pigging trials and Factory Acceptance Testing (FAT) under client witness was also conducted to ensure this new approach for pipeline isolation would meet the client’s safety, integrity and operational requirements.
The Remote Tecno Plug was configured in a three-module arrangement and pigged 40 m to the isolation location. Once the plug was set, the isolation was proven via STATS’ secondary and primary leak tests before an isolation certificate was issued allowing the valve repairs to be safely completed. The tool was then unset and reverse pigged to the receiver within the client’s desired 24-hour outage window.
STATS Group conducts major international piping and pipeline integrity maintenance projects and operates from Edmonton and Calgary, with support from its Houston base and UK headquarters near Aberdeen, Scotland.